For a minimal Z20X configuration, only the Main Board is required, and the interface with it can be done with a serial terminal program via the USB port. In a typical configuration though, a Z20X system consists of four PCBs – the Main Board, the Processor Module, the LCD panel, and the Expander. Several possible ways exist to physically arrange the boards – with or without LCD, with or without the Expander, and also depending on how the display and expansion connectors are installed – straight or right angle.
The "standard" way is shown in the picture below. It includes the LCD panel and the Expander. The Main Board in the same geometric plane as the LCD, and the Expander perpendicular to both.
One mechanical challenge during assembly is when the LCD and the Main Board get connected together. Since the LCD’s connector is on one side only, the other side of the sandwich will be "flopping", unless there is something underneath to provide additional support. The release revision of the Z20X board includes an additional M4 hole situated just under the sound chip to allow installation of a flat-bottom 11mm height plastic board supporter. The bottom side of it can then be affixed to the LCD board by a small piece of dual-sided tape.
This approach produces a good and stable assembly, even without the use of an external enclosure, and leaves the four corner mounting holes available for further use with an enclosure. The alternative way would be to use the mounting holes with 11mm spacers and 16mm length M3 screw and nut pairs.